THE ZEEMAN EFFECT IN THE OPTICAL SPECTRUM OF

THE ZEEMAN EFFECT IN THE OPTICAL SPECTRUM OF MANGANESE MONOHYDRIDE: Mn. H. Jamie Gengler and Timothy C. Steimle Department of Chemistry and Biochemistry Arizona State University Tempe, AZ 85287 -1604 Michael Stoll Molecular Physics Fritz-Haber-Institut der Max-Planck-Gessellschaft Faradayweg 4 -6, 14195 Berlin, Germany June 18, 2007

Motivation. Magnetic trapping of molecules. Ideal candidates have: 1) Unpaired electrons (freeradicals) for nonzero magnetic moment. 2) Large rotational constant for well separated spectral features (diatomic hydrides). So far, NH and Ca. H have been successfully trapped. J. D. Weinstein, R. de. Carvalho, T. Guillet, B. Friederich, and J. M. Doyle, Nature (London), 395, 148 -150 (1998).

Mn. H Considerations. 1) Optical A-X (0, 0) transition near 17500 cm-1 is ideal for LIF monitoring of magnetic trap spatial and temporal Mn. H concentrations. 2) X 7 S+ and A 7 P states have s = 6 B. 3) Rotational constants of B(X 7 S+) = 5. 606 cm-1 and B(A 7 P) = 6. 348 cm-1. 4) The X 7 S+ state has much smaller fine-structure parameters of l = -0. 004 cm-1 and g = 0. 03 cm-1. 5) The spectra is complicated by hyperfine interactions from both the 55 Mn (I = 5/2) and 1 H (I = 1/2) nuclei.

Laser Induced Fluorescence. Helmholtz coils pre-amp Gated photon PMT counter Lens board Mn rod (rotated by stepper motor) Molecular beam Mirror CW Ring. Dye Laser * Nd: YAG *355 nm (10 m. J) Optical filter IEEE computer 20 Hz 10 -6 10 -5 torr * I 2 , etalon diffusion pump Burleigh RS 232 serial wavemeter computer board H 2 300 psi 20 Hz solenoid pulsed valve * * (variable time delay) * D/A computer board

Magnetic Fields. Helmholtz coils (electromagnet) Polarization of the laser can be rotated by 900 for parallel “||” or perpendicular “┴” orientation.

Zeeman Spectra. P 1(0) Field. Free 1435 Gauss Exp. Model TROT=100 K FWHM=75 MHz 17568. 1 17568. 2 17568. 3 17568. 4 17568. 5 Laser Wavenumber (cm-1) 17568. 6 17568. 7

Zeeman Spectra. P 1(0) Field. Free 1449 Gauss Exp. Model TROT=100 K FWHM=75 MHz 17568. 1 17568. 2 17568. 3 17568. 4 17568. 5 Laser Wavenumber (cm-1) 17568. 6 17568. 7

Magnetic Trapping. Buffer-gas loading Freezing out of buffer-gas t ~ 5 s 3 He/4 He-Dilution refrigerator for reaching the m. K regime base temperature: 100 m. K Copper cell Magnet Quadrupole Magnet 2. 3 T Trap depth: 0. 67 K B-1 T-1

Magnetic Trapping.

Magnetic Trapping.

Conclusions / Future Work. 1) Molecular beam data closely modeled by simple Zeeman Hamiltonian (RMS ~ 100 MHz, no significant perturbations). 2) Continue refining Zeeman model. Possible inclusion of other branch features and/or anisotropic g-factors. 3) Successful demonstration of magnetically trapping Mn. H. 4) Determine both elastic and inelastic cross-sections. 5) THANK YOU!!